watchexec

Software development often involves running the same commands over and over. Boring!

watchexec is a simple, standalone tool that watches a path and runs a command whenever it detects modifications.

Example use cases:

Features

Simple invocation and use
Runs on OS X, Linux and Windows
Monitors current directory and all subdirectories for changes (use --watch to override)
- Uses most efficient event polling mechanism for your platform (except for BSD)
Coalesces multiple filesystem events into one, for editors that use swap/backup files during saving
By default, uses .gitignore to determine which files to ignore notifications for
Support for watching files with a specific extension
Support for filtering/ignoring events based on glob patterns
Launches child processes in a new process group
Sets $WATCHEXEC_UPDATED_PATH in the environment of the child process to the first file that triggered a change
Optionally clears screen between executions
Optionally restarts the command with every modification (good for servers)
Does not require a language runtime

Watch all JavaScript, CSS and HTML files in the current directory and all subdirectories for changes, running make when a change is detected:

$ watchexec --exts js,css,html make

Watch all files below src and subdirectories for changes, running make test when a change is detected:

$ watchexec --watch src make test

Call make test when any file changes in this directory/subdirectory, except for everything below target:

$ watchexec -i target make test

Call/restart python server.py when any Python file in the current directory (and all subdirectories) changes:

$ watchexec -e py -r python server.py

Run make when any file changes, using the .gitignore file in the current directory to filter:

$ watchexec make

If you're running nightly Rust, install it using cargo:

$ cargo install watchexec

If you're using rustup, install it like this:

$ rustup toolchain install nightly
$ rustup run nightly cargo install watchexec

$ brew install https://raw.githubusercontent.com/mattgreen/watchexec/master/pkg/brew/watchexec.rb

For now, use the GitHub Releases tab to obtain the binary. PRs for packaging in various distros are welcomed.

Use the GitHub Releases tab to obtain the binary. In the future, I'll look at adding it to Chocolatey.

Currently, watchexec requires a recent nightly Rust to build, due to use of unstable features.